Activation member and subassembly for a medicament delivery device

Abstract

The present disclosure provides an activation member for a medicament delivery device comprising an outer part and an inner part coaxially connected to the outer part. The outer part comprises a needle cover contact surface and the inner part comprises at least one flexible arm having an inclined end surface and a plunger rod support at its distal end. The inner part further comprises at least two spring supports configured to support a distal end of a drive spring of the medicament delivery device. The plunger rod support is configured to engage with a plunger rod of the medicament delivery device in order to inhibit a proximal movement of the plunger and the inclined end surface is configured to interact with a distal end part of the medicament delivery device, thereby disengaging the plunger rod support from the plunger rod, when the activation member is distally displaced by a needle cover of the medicament delivery device.

1 - 16 . (canceled) 
     
     
         17 . An activation member for a medicament delivery device, wherein the activation member extends along a longitudinal axis from a proximal to a distal end, the activation member comprising:
 an outer part and an inner part coaxially connected to the outer part, wherein the outer part comprises a needle cover contact surface configured to contact a needle cover of the medicament delivery device, and wherein the inner part comprises at least one flexible arm extending distally and having an inclined end surface and a plunger rod support at its distal end, the inclined end surface being in proximal direction inclined in a radial inward direction; and   at least two spring supports each extending distally and being configured to support a distal end of a drive spring of the medicament delivery device, wherein the plunger rod support is configured to engage with a plunger rod of the medicament delivery device in order to inhibit a proximal movement of the plunger rod, and wherein the inclined end surface is configured to interact with a distal end part of the medicament delivery device, causing a radial outward deflection of the at least one flexible arm thereby disengaging the plunger rod support from the plunger rod, when the activation member is distally displaced by the needle cover.   
     
     
         18 . The activation member of  claim 17 , wherein a circumferential surface of the inner part is formed of the at least one flexible arm, the at least two spring supports, and at least one slot between each flexible arm and each spring support, wherein the at least one slot is configured to kinematically decouple the deflection of each flexible arm from the spring supports. 
     
     
         19 . The activation member of  claim 17 , wherein the inner part and the outer part overlap along a part of their length. 
     
     
         20 . The activation member of  claim 17 , wherein the outer part is connected to or integral with the inner part via at least one support extending radially between at least one of the spring supports and a connection structure of the outer part. 
     
     
         21 . The activation member of  claim 17 , wherein each plunger rod support has a radially inwards extending protrusion configured to form a stop surface for engagement with a distal portion of the plunger rod. 
     
     
         22 . The activation member of  claim 17 , wherein each spring support comprises a protrusion or step extending radially inwards and having a proximally facing support surface configured to support the distal end of the drive spring. 
     
     
         23 . The activation member of  claim 17 , further comprising a distal spring support surface configured to interact with a distal spring of the medicament delivery device, wherein the distal spring support surface is formed by the support or a distal end surface of the connection structure. 
     
     
         24 . The activation member of  claim 17 , wherein the at least one flexible arm and the at least two spring supports are alternately arranged in circumferential direction. 
     
     
         25 . The activation member of any one of  claim 24 , wherein the proximally facing support surface of the protrusion or step of the spring support is located more proximal compared to the distally facing stop surface of the radially inwards extending protrusion of the plunger rod support. 
     
     
         26 . A subassembly for a medicament delivery device, the subassembly comprising:
 a distal housing;   an activation member according to any one of the preceding claims, wherein the activation member is coaxially arranged within the distal housing and distally movable in relation to the distal housing;   a plunger rod coaxially arranged within the activation member and releasably connected to the plunger rod support of the activation member;   a drive spring coaxially arranged between the plunger rod and the spring supports of the activation member, wherein a distal end of the drive spring is supported by the spring supports and a proximal end of the drive spring is supported by a proximal ledge of the plunger rod;   a distal end cap connected to the distal housing; and   a distal spring arranged between the distal end cap and the activation member configured to apply a biasing force on the activation member.   
     
     
         27 . The subassembly of  claim 26 , wherein the distal end cap comprises a guide hole along the longitudinal axis of the medicament delivery device configured to axially guide the distal end of the plunger rod when the activation member is distally displaced. 
     
     
         28 . The subassembly of  claim 26 , wherein the distal end cap comprises a displacement structure configured to interact with the inclined end surface of the at least one flexible arm in order to radially deflect the at least one flexible arm such that the plunger rod support is disengaged from the plunger rod, when the activation member is distally displaced. 
     
     
         29 . The subassembly of  claim 28 , wherein the displacement structure is rigid and is radially inclined, preferably with the same angle of inclination as the inclined end surface of the at least one flexible arm. 
     
     
         30 . A medicament delivery device comprising a distal subassembly and a proximal subassembly, wherein the distal subassembly is the subassembly of  claim 26 . 
     
     
         31 . The medicament delivery device of  claim 30 , wherein the proximal subassembly comprises:
 a proximal housing connectable to the distal housing;   a rotator coaxially connected to a distal inner part of the proximal housing and movable in relation to the proximal housing;   a displaceable needle cover partially arranged within the proximal housing;   a medicament container holder connected through the needle cover and the rotator to the proximal housing and configured to receive a medicament container; and   a needle cover spring disposed between the needle cover and the medicament container holder and configured to apply a biasing force on the needle cover,   wherein the needle cover is axially movable inside at least the proximal housing such that a distal end of the needle cover contacts the contact surface of the activation member whereby the activation member is distally displaced.   
     
     
         32 . The medicament delivery device of  claim 30 , wherein the medicament delivery device is a disposable single-dose auto-injector.